The most surprising thing about "Her," the new Spike Jonze movie, is not that it dares to suggest an otherwise sane person might fall in love with the operating system that runs his computer and his smartphone. Or that middle-aged men look good in high-waisted pants. Or that it will be possible someday soon to ride a subway from downtown Los Angeles to the beach.

It is something simpler: that the near future is more interesting, culturally and architecturally, than the recent past.

Thanks to the digital revolution of the last two decades, it has become remarkably easy for filmmakers — and for songwriters, architects, novelists and car designers — to dip into a bottomless back catalog and borrow or remix work from the past.

This hasn't just produced a rampant anachronism in popular culture, with artists of all kinds churning through what the British music critic Simon Reynolds has called "Retromania." It has also made the future a lonelier and less appealing place.

There have still been movies imagining life 50 or 100 years from now, of course, during this period of wide-ranging cultural nostalgia. But they've tended to portray violent dystopias or post-apocalyptic wastelands. And star Tom Cruise.

And increasingly they have been pushed aside in the cultural conversation by films and TV series — "Computer Chess," "The Way Way Back," "Downton Abbey," "Mad Men," "Inside Llewyn Davis" — that either re-create an entire historic era with detailed ease or seem to exist in a nimble time machine, mixing elements of past and present the way a Spotify user can jump from Lorde to KRS-One and back again.

"Her" bucks the retro moment by jumping enthusiastically, and blindly, into a future that is neither utopian nor dystopian but — like our own era, and like every era —somewhere in the slippery in-between. The film is set in the Los Angeles of two or three decades from now; the year is never specified.

The city has dense clusters of tall towers and a mass-transit system to rival London's. Cars seem to have been banished. The thoughtful but hopelessly needy hero, Theodore Twombly, lives in a large and serene apartment in a downtown high-rise and either walks or takes the train everywhere.

The sidewalks and the rail stations are crowded with people. It's as if a benevolent Robert Moses, a planning dictator with a green agenda, had taken over the political realm in Los Angeles.

To create this colorfully remade L.A., Jonze and his production designer, K.K. Barrett, digitally plumped up the city's existing skyline. Jonze spoke at some length as he was preparing the movie with the New York architect Elizabeth Diller, whose firm is designing Eli Broad's new contemporary art museum in downtown Los Angeles.

The filmmakers also shot a number of scenes in Shanghai's Pudong district, which not only has an impressive collection of new skyscrapers but is laced with pedestrian sky bridges that allowed Jonze to film his actors without worrying whether the cars in the background looked futuristic enough.

The double setting also highlights the movie's interest in themes connected to surrogacy: to one person or thing standing in for another.

The operating system, called Samantha, stands in for the real girlfriend Theodore can't seem to find after his divorce. A young woman stands in for Samantha in what turns out to be a disastrous attempt at sexual intimacy between man and software.

Theodore stands in for the people who hire him, in his job at the candy-colored offices of a company called BeautifulHandwrittenLetters.com, to ghost-write personal notes to friends and relatives. In the same way, Shanghai stands in for the future Los Angeles.

Surrogacy, of course, is a basic ingredient of moviemaking. Actors stand in for characters made up by screenwriters. The action captured on film stands in for real life.

And Los Angeles has always stood in on-screen for other cities. The generic quality of its downtown streets in particular has made it attractive to directors of feature films and car commercials alike.

But another city standing in for the Los Angeles of the future? That's new, or at least extremely rare. And Jonze doesn't just do it simply because Shanghai looks more believably dense and developed than present-day Los Angeles.

Filming in Shanghai also allows him to capture something significant about the character, and the anxieties, of contemporary L.A. This is a city caught in limbo between two very different kinds of urbanism: between its private and car-dominated past and denser, more public and more connected future.